Could this be proof that even the high-performance version of the new Subaru WRX is growing up?

Until now it has traditionally been that whereas the WRX has been the darling of the boy-racer set, the STI models have been the choice of the more serious performance enthusiasts.

These have been the WRX models that have been given the treatment by Subaru Tecnica International, the motorsports division of Fuji Heavy Industries, since 1994.

Under the skin they have undergone various treatments all in the interests of high-performance motoring, while their exteriors have traditionally featured two things - the famous cherry blossom red STI badging, and among the biggest rear spoilers you will ever see.

Now a brand-new model has arrived in New Zealand, and while the badging remains a permanent fixture, the large rear wing is a deleteable option.

This begs an obvious question - does this mean the STI is getting all domesticated? Is it going the way of the new WRX which is now being marketed as a car for grown-ups who maybe don't want to be part of any WRX perception of backwards caps and cowboys in go-karts. One of the great quotes from the launch of that car earlier this year came from Subaru NZ boss Wally Dumper who described the latest WRX as "Goodbye boy racer - and hello sophisticated fun".

With the STI, Dumper says his company realises some customers prefer a more subtle style and don't necessarily want to make such a bold statement on the road with the big wing.

"So it's an option," he adds.

"But having said that we are also very cognisant of the fact that Subaru drivers share an ‘attitude' more than the typical demographic other brands may share. So our advertising for STI complements that Kiwi Subaru attitude and will feature the wing, which has been synonymous with the STI up until now."

And that's OK too, because the latest STI remains a potent machine capable of - as Subaru NZ says in its marketing blurb - going like a vegan out of a steakhouse.

Whereas the WRX is powered by a new direct-injected 2.0-litre engine that offers 197 kilowatts of power and 350 newton metres of torque and is available with a choice of manual and automatic transmissions, the STI carries over a 2.5-litre turbocharged four that develops 221kW of power and 407Nm of torque.

The engine is mated exclusively to a short-throw six-speed manual transmission, and when driven with enthusiasm the AWD sedan can scoot to the open road speed limit in just 4.9 seconds.

It can handle too, thanks to its drivability being honed in development testing in several countries, including ultra-high speed road driving on Germany's challenging Nurburgring circuit.

A major ingredient to the STI's potency is a multi-mode Driver's Control Centre Differential (DCCD) which allows drivers to vary the amount of power and torque fed to the front and rear axles.

The default setting is Auto which allows all-round control across a broad range of driving conditions, with the torque applied to each axle automatically varying by around 50 per cent depending on the driving environment. But if Auto Plus mode is chosen the torque is biased towards the front wheels, Auto Minus sends more torque to the rear wheels, while a Manual mode allows the driver to decide how much torque is distributed to the front or rear wheels.

The sedan also features Active Torque Vectoring which improves near-limit cornering performance by braking the inner front wheels and distributing torque to the outer front wheel. And that can also be controlled by the person behind the wheel, who can either turn it off altogether to help get out of certain slippery conditions such as mud or snow, or select a Traction mode which cancels the car's on-board Vehicle Dynamics Control and Traction Control while keeping the Torque Vectoring still active - effective on race tracks.

This latest STI uses the same bodyshell as the WRX sedan, with the big differences being that optional rear wing and fitment of new design 18-inch alloy wheels, with the option of lightweight BBS versions on the Premium variant. The new model features Brembo brakes, distinguished visually by a white STI logo on the black painted callipers.

The front grille has unique mesh treatment, and there is STI badging front, rear and sides. For the first time, the STI also has daytime running lights.

Other standard features now include factory-fitted satellite navigation, reversing camera, dusk-sensing LED headlights with halogen high-beam, rain sensing wipers, a shark fin radio antenna, and dual-zone climate control air conditioning.

Despite the fact the new WRX STI is obviously the most sophisticated and comfortable of the model line thus far, it remains entrenched as the brand's ultimate performance flagship - even if it can be specified without the traditional large rear wing.

Pricing looks attractive too. The list price of $59,990 for the base version is $1500 less than the previous manual model, while the Premium model is tagged at $64,990. Very good prices for what is one of the most exhilarating sedans on the market.